Pressure pulse/shock wave method for generating waves having plane, nearly plane, convergent off target or divergent characteristics

ABSTRACT

An apparatus for generating pressure pulse/shock waves (PP/SWs) is disclosed which comprises a pressure pulse/shock wave (PP/SW) source, a housing enclosing said PP/SW source, and an exit window from which wave fronts of waves generated by said PP/SW source emanate. The wave fronts have plane, nearly plane, convergent off target or divergent characteristics. In one embodiment, an extracorporeal shock wave system provides a planar wave for the treatment of tissue. A parabolic reflector is provided in order to propagate the planar wave through a membrane and to the tissue of a human subject. A piezoelectric, electrohydraulic or electromagnetic source may be used to develop the wave.

RELATED APPLICATIONS

This application is a divisional of co-pending U.S. application Ser. No.11/959,868 filed on Dec. 19, 2007 which is a continuation in part ofabandoned U.S. application Ser. No. 11/071,156, filed Mar. 4, 2005entitled “Pressure Pulse/Shock Wave Apparatus for Generating WavesHaving Nearly Plane or Divergent Characteristics” which also claimed thebenefit of U.S. Provisional Patent Application Ser. No. 60/621,028,filed Oct. 22, 2004 and of U.S. Provisional Patent Application Ser. No.60/642,149, filed Jan. 10, 2005, and abandoned U.S. application Ser. No.10/708,249 filed Feb. 19, 2004 entitled “Shock Wave Therapy Method andDevice” which also claimed benefit to provisional applications60/448,981 filed Feb. 19, 2003 and 60/448,979 filed Feb. 19, 2003 andalso to U.S. patent application Ser. No. 11/122,154, filed May 4, 2005entitled “Pressure Pulse/Shock Wave Therapy Methods and an Apparatus forConducting the Therapeutic Methods” now U.S. Pat. No. 7,470,240 grantedon Dec. 30, 2008, the disclosures of which are incorporated herein byreference in their entirety.

FIELD OF THE INVENTION

The invention relates to an apparatus which generates acousticalpressure pulse/shock waves having wave fronts with plane, nearly plane,convergent off target or divergent characteristics for applications inhuman and veterinary medicine.

BACKGROUND OF THE INVENTION

The present application relates to extracorporeal shock wave technologyand in particular, an electromagnetic, electrohydraulic or piezoelectricshock wave device that propagates planar waves, and to methods of usingsuch a device, for developing shock waves and for treating tissue.

Shock waves are used in different medical disciplines and in differentspecies. Although it is not known exactly how specific tissue respondsto the shock wave, it is proven that shock waves can have a therapeuticeffect and improve certain medical conditions.

In urology, the shock wave is used to disintegrate kidney or urethrastones. In orthopedics, shock waves are used to stimulate bone growth innon-unions. Shock wave therapy is further used to treat epicondylitis,tendonitis calcarea of the shoulder, achillodynia calcaneal spurs, andmany other conditions. Shock waves are also used in veterinary medicineto treat ligaments, tendons, splint bone fractures, navicular syndrome,back pain, and certain joint conditions.

Commercially available devices use either high-energy focused shock wavesystems or radial emitting pressure pulse systems. In these systems theshock wave is generated either by an electrical discharge in a liquid(electro hydraulic), electrical discharge in an electrical coil thatdrives a diaphragm (electro magnetic), electrical discharge in piezoelements (piezo electric) or a projectile that hits its target(ballistic system).

Focused shock wave systems have an advantage over radial systems becausethe shock wave reaches its maximal density inside the body. This allowsfor the treatment of deeper tissue inside the body. Typical penetrationdepths in orthopedic devices are 100 mm in human medicine or up to 80 mmin veterinary medicine.

Radial systems can only treat superficial conditions because thediverging wave loses energy density with the square of the distance tothe source, leading to insufficient energy density to show an effect ondeeper tissue inside the body.

Investigations have shown that, for a tissue to respond, the shock wavemust reach a certain energy density measured in mJ/mm.sup.2 (milliJoules per square millimeter).

Also the volume of the treated tissue (or area for rathertwo-dimensional treatment regions, such as tendons) plays an importantfactor. Treatment results show that these two factors have the majorinfluence on the clinical outcome.

Focused systems have enough energy density in deeper regions but thetreatment area is often too small. Either the shock wave source or thepatient must be moved to treat a bigger area.

Radial systems treat a bigger area, but the power density is too smallto show an effect in deeper tissues.

Electro-hydraulic shock wave systems have been used to disintegratekidney and urethral stones by applying focused shock waves to the stone.A few hundred up to a few thousand shock waves may be required to breaka stone within a mammal into small pieces of 3-4 mm diameter which areable to pass over a period of several weeks through the urethra and thebladder out of the patient's body.

Devices using electro-hydraulic (U.S. Pat. No. 4,539,989), piezoceramic(U.S. Pat. No. 5,119,801) or electromagnetic (U.S. Pat. No. 5,174,280)shock wave or pressure pulse generating elements have been described.

The patents used herein to illustrate the invention and, in particular,to provide additional details respecting the practice are incorporatedherein by reference in their entirety.

In certain of non-urological applications, shock waves and pressurepulses may be used to treat/cure orthopedic painful conditions. Thetreated indications may be related to tendons, ligaments, soft tissueand include muscle pain and calcification in tissue. Suitable devicesand procedures have been described (U.S. Pat. No. 5,545,124 and U.S.Pat. No. 5,595,178). The treatment of tissue with shock waves has alsobeen discussed (United States Patent Application 2004/0162508).

In certain non-urological applications, shock waves are used to treatischemic heart tissue for generating better blood supply in the treatedtissue and thus recover the tissue's functionality.

Known devices generally make use of more or less strong focused shockwaves which are focused by ellipsoidal reflectors in electro-hydraulicdevices (U.S. Pat. No. 4,539,989) or by parabolic reflectors in devicesusing electromagnetic sources which are emitting waves from acylindrical surface (U.S. Pat. No. 5,174,280). Other electromagneticsources may make use of acoustic lenses of different shapes, forexample, concave or convex, depending on the sound velocity and densityof the lens material used (U.S. Pat. No. 5,419,335 and European Patent 1445 758 A2). Piezoelectric sources often use spherical surfaces to emitacoustic pressure waves which are self focused to the center of thesphere (U.S. Pat. No. 5,222,484). The same type of focusing has beenused in spherical electromagnetic devices (U.S. Pat. No. 4,807,627).

There is a need for an apparatus and a process for optimizedelectro-hydraulic pressure pulse generation by changing the focusingcharacteristics of a pressure pulse or shock wave so that unfocused wavefronts with plane or nearly plane acoustic wave front and/or convergentoff target or divergent acoustic wave front characteristics can bereleased by the apparatus. As used herein, convergent off target iswhere the focal region or point is moved away from the treated tissue.

There is also a need for an apparatus for optimized pressure pulse/shockwave generation, wherein waves with defined wave front characteristics,like focused and/or plane, nearly plane, convergent off target and/ordivergent are released from the apparatus for treating tissues, inparticular, for treating soft tissue, skin or skin near conditionsincluding, but not limited to, skin and skin near conditions caused bytrauma or diseases.

There is also a need for providing an apparatus that allows treatmentwithout requiring extensive scanning of the area to be treated. This isusually required to cover an area uniformly if apparatuses using a smallfocal point are used. Such an apparatus would reduce treatment times.

There is a need for an apparatus that produces waves having plane,nearly plane, convergent off target or divergent acoustic wave frontcharacteristics with adjustably reducible or reduced energy densitiescompared to wave fronts emitted by focused shock wave generators.

There is also a need for an apparatus and method that allows usingexisting pressure pulse generating devices to treat tissues which havemore area like than volume like characteristics, such as skin.

The task of the present invention is to optimize the interaction of theshock wave with the tissue of a subject being treated so as to achievethe best clinical result. This task is accomplished by using high-energyshock waves that are generated by electro hydraulic, electro magnetic,or piezoelectric means, but not focused into a focal point. Instead, theshock wave is reflected or refracted in such a way that a “plane wave”or “flat wave” is emitted from the source.

With a “plane” or “flat” wave, the energy is neither converging (as withthe focused shock wave) or diverging (as with a radial wave). Rather theenergy distribution over the emitting area stays the same even indifferent distances along the axis of the shock wave source. The initialshock wave energy must be enough to reach a certain energy density atthe distal end of the shock wave source.

SUMMARY OF THE INVENTION

The present invention provides for an apparatus for generating pressurepulse/shock waves comprising: a pressure pulse/shock wave (PP/SW)source, a housing enclosing said PP/SW source, and an exit window fromwhich wave fronts of waves generated by said PP/SW source emanate,wherein said wave fronts have plane, nearly plane, convergent off targetor divergent characteristics.

The PP/SW source may comprise a pressure pulse/shock wave generatingelement for generating pressure pulses/shock waves, a focusing elementfor focusing the waves into a focus volume outside the focusing element.The apparatus may further comprise a movable elongated mechanicalelement having a longitudinal axis, wherein said focus volume issituated on or at said longitudinal axis, and said movable elongatedmechanical element is movable to extend to or beyond said focus volumeso that wave fronts with divergent characteristics emanate from saidexit window. The movable elongated element may be part of the housingand the exit window may be a window of the housing. The focusing elementmay be an acoustic lens, a reflector or a combination thereof.

The PP/SW source may also comprise a pressure pulse/shock wavegenerating element and waves emanate from the exit window of the housingwithout being focused by a focusing element.

The PP/SW source may also comprise an electro-hydraulic pressurepulse/shock wave generating element. The element may comprise at leasttwo electrodes. In this case, the PP/SW source may also comprise ageneralized paraboloid according to the formula y^(n)=2px, wherein x andy are cartesian coordinates, p/2 is a focal point measured from an apexof the generalized paraboloid, and n is about 1.2<2 or 2< about 2.8,with n≠2.

The electrodes may be positioned within the generalized paraboloid, anda spark between tips of said electrodes may be, with about +/−5 mm ofvariance, generated at the focal point p/2 of the generalizedparaboloid. The burn down of the electrode tips (z) may be compensatedby the selection of (p+/−z) and n so that the resulting generalizedparaboloid has a configuration between a paraboloid defined by formulay²=2(p+z)x and a paraboloid defined by formula y²=2(p−z)x.

The PP/SW source may also comprise an electromagnetic pressurepulse/shock wave generating element. The electromagnetic pressurepulse/shock wave generating element may be an electromagnetic flat orcurved emitter emitting waves having nearly plane or divergentcharacteristics, and wherein the waves emanate from said exit windowwithout being further modified by a lens. The electromagnetic pressurepulse/shock wave generating element may also be an electromagnetic flatemitter emitting waves having nearly plane characteristics. Here, thePP/SW source may further comprise a lens for focusing said waves in afirst focal point, wherein divergent waves generated behind said focalpoint and emanate from the exit window. The PP/SW source mayalternatively comprise at least one lens for de-focusing said waves sothat waves with divergent wave characteristics emanate from the exitwindow.

The electromagnetic pressure pulse/shock wave generating element mayalso be an electromagnetic cylindrical emitter. Here, the PP/SW sourcemay further comprise at least one reflecting element and/or at least onelens.

The PP/SW source may also comprise a piezoceramic pressure pulse/shockwave generating element. The piezoceramic pressure pulse/shock wavegenerating element may be a piezoceramic flat or curved emittergenerating waves having nearly plane or divergent characteristics, andwherein said waves emanate from said exit window without being modifiedby a lens. The curved emitter may have a curved piezoceramic emittingsurface generating waves having divergent characteristics. Thepiezoceramic pressure pulse/shock wave generating element may also be apiezoceramic flat emitter for emitting waves having nearly planecharacteristics. Here, the PP/SW source may further comprise a lens forfocusing said waves in a first focal point, wherein divergent wavesgenerated behind said first focal point emanate at said exit window. ThePP/SW source may alternatively further comprise at least one lens forde-focusing said waves into divergent waves so that waves with divergentwave characteristics emanate from the exit window.

The piezoceramic pressure pulse/shock wave generating element may alsobe a piezoceramic cylindrical emitter. Here, the PP/SW source mayfurther comprise at least one reflecting element and/or at least onelens.

The present invention pertains to a shock wave device comprising areflector housing, a parabolic reflector disposed in the housing, and anenergy source disposed within the reflector for developing a shock waveso that a planar shock wave is formed by the reflector and emanates fromthe housing. In an embodiment, the reflector is shaped and dimensionedto provide a reflected wave having a power density level to produce atissue reaction in a subject to which the wave is administered. In anembodiment, the power density may be in the range of approximately 0.01mJ/mm.sup.2 to 1.0 mJ/mm.sup.2. In an embodiment, the opening of theparaboloid may have a diameter in the range of approximately 20 mm to100 mm. In an embodiment, the distance between the origin point of theparaboloid to a propagation point may be in the range of approximately 3mm to 10 mm.

In an embodiment, the energy source may be an electro hydraulic source.In an embodiment, the energy source may have a propagation pointcentered approximately at the focal point of the parabolic reflector. Inan embodiment, the energy source may comprise a pair of electrode tipsconnected to a capacitor. In an embodiment, the energy source may have apropagation point centered approximately between the electrode tips. Inan embodiment, the reflector may include a cavity having an openingsealed by a membrane. In an embodiment, the cavity may contain a fluid.In an embodiment, the fluid may be water.

An embodiment of the invention may provide for a method for developing aplanar shock wave to be used for therapeutic purposes on a subject, themethod comprising the steps of generating a spark to cause a shock wave,shaping and directing the shock wave to create a planar wave andpropagating the planar shock wave toward the subject. In an embodiment,the method may further comprise the steps of providing a device having aparabolic reflector, an energy source attached to an electrode tip and amembrane disposed across a cavity in communication with the parabolicreflector, orienting the electrode tip at a focal point of the parabolicreflector, generating a spark at the electrode tip and developing ashock wave, propagating the shock wave so that it reflects at theparabolic reflector, forming a planar wave, propagating the planar wavethrough the membrane and toward tissue of a subject to receive theplanar wave for therapeutic effect.

An embodiment of the invention provides a method for treating tissuecomprising the steps of generating a planar shock wave and coupling theplanar shock wave to the tissue to be treated. In an embodiment, themethod may further comprise the steps of providing a treatment devicethat develops a shock wave, orienting the treatment device adjacent tothe tissue area, forming a planar shock wave to be propagated from thetreatment device and to be dispersed through the tissue and activatingthe tissue in order to cause a chemical release from the tissue cells.In an embodiment, the shockwave may be developed by electro hydraulic,electromagnetic or piezoelectric means. In an embodiment, the method maycomprise the steps of generating a spark by an electrode tip to developthe shockwave and reflecting the shockwave from a parabolic reflector.In an embodiment, the tissue is activated to release a protein forgenerating an immune response.

An embodiment of the invention provides for a therapeutic device foradministering a shock wave to a subject comprising a housing, a shockwave source disposed in the housing, wave directing and shapingstructure in the housing responsive to the shock wave for causing aplanar shock wave to be emitted from the housing, and structure forcoupling the shock wave to the subject. In and embodiment the wavedirecting and shaping structure includes a parabolic reflector. In anembodiment the housing includes an opening and the coupling structureincludes a membrane disposed across the opening. In an embodiment thewave directing and shaping structure is disposed in a cavity having theopening. In an embodiment the shock wave source includes an electrodethat develops a spark.

DEFINITIONS

A “curved emitter” is an emitter having a curved reflecting (orfocusing) or emitting surface and includes, but is not limited to,emitters having ellipsoidal, parabolic, quasi parabolic (generalparaboloid) or spherical reflector/reflecting or emitting elements.Curved emitters having a curved reflecting or focusing element generallyproduce waves having focused wave fronts, while curved emitters having acurved emitting surfaces generally produce wave having divergent wavefronts.

“Divergent waves” in the context of the present invention are all waveswhich are not focused and are not plane or nearly plane. Divergent wavesalso include waves which only seem to have a focus or source from whichthe waves are transmitted. The wave fronts of divergent waves havedivergent characteristics. Divergent waves can be created in manydifferent ways, for example: A focused wave will become divergent onceit has passed through the focal point. Spherical waves are also includedin this definition of divergent waves and have wave fronts withdivergent characteristics.

A “generalized paraboloid” according to the present invention is also athree-dimensional bowl. In two dimensions (in Cartesian coordinates, xand y) the formula y^(n)=2px [with n being≠2, but being greater thanabout 1.2 and smaller than 2, or greater than 2 but smaller than about2.8]. In a generalized paraboloid, the characteristics of the wavefronts created by electrodes located within the generalized paraboloidmay be corrected by the selection of (p (−z,+z)), with z being a measurefor the burn down of an electrode, and n, so that phenomena including,but not limited to, burn down of the tip of an electrode (−z,+z) and/ordisturbances caused by diffraction at the aperture of the paraboloid arecompensated for.

“Nearly plane waves” also do not have a focus to which their fronts move(focused) or from which the fronts are emitted (divergent). Theamplitude of their wave fronts (having “nearly plane” characteristics)are approximating the constancy of plain waves. “Nearly plane” waves canbe emitted by generators having pressure pulse/shock wave generatingelements with flat emitters or curved emitters. Curved emitters maycomprise a generalized paraboloid that allows waves having nearly planecharacteristics to be emitted.

A “paraboloid” according to the present invention is a three-dimensionalreflecting bowl. In two dimensions (in Cartesian coordinates, x and y)the formula y²=2px, wherein p/2 is the distance of the focal point ofthe paraboloid from its apex, defines the paraboloid. Rotation of thetwo-dimensional figure defined by this formula around its longitudinalaxis generates a de facto paraboloid.

“Plane waves” are sometimes also called flat or even waves. Their wavefronts have plane characteristics (also called even or parallelcharacteristics). The amplitude in a wave front is constant and the“curvature” is flat (that is why these waves are sometimes called flatwaves). Plane waves do not have a focus to which their fronts move(focused) or from which the fronts are emitted (divergent).

A “pressure pulse” according to the present invention is an acousticpulse which includes several cycles of positive and negative pressure.The amplitude of the positive part of such a cycle should be above about0.1 MPa and its time duration is from below a microsecond to about asecond. Rise times of the positive part of the first pressure cycle maybe in the range of nano-seconds (ns) up to some milli-seconds (ms). Veryfast pressure pulses are called shock waves. Shock waves used in medicalapplications do have amplitudes above 0.1 MPa and rise times of theamplitude are below 100 ns. The duration of a shock wave is typicallybelow 1-3 micro-seconds (μs) for the positive part of a cycle andtypically above some micro-seconds for the negative part of a cycle.

Waves/wave fronts described as being “focused” or “having focusingcharacteristics” means in the context of the present invention that therespective waves or wave fronts are traveling and increase theiramplitude in direction of the focal point. Per definition the energy ofthe wave will be at a maximum in the focal point or, if there is a focalshift in this point, the energy is at a maximum near the geometricalfocal point. Both the maximum energy and the maximal pressure amplitudemay be used to define the focal point.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of facilitating an understanding of the invention, thereis illustrated in the accompanying drawings an embodiment thereof, froman inspection of which, when considered in connection with the followingdescription, its construction and operation, and many of its advantagesshould be readily understood and appreciated.

FIG. 1 is a diagrammatic view of a section through a prior art shockwave device propagating a focused wave; and

FIG. 1 a is a simplified depiction of a pressure pulse/shock wave(PP/SW) generator with focusing wave characteristics.

FIG. 1 b is a simplified depiction of a pressure pulse/shock wavegenerator with plane wave characteristics.

FIG. 1 c is a simplified depiction of a pressure pulse/shock wavegenerator with divergent wave characteristics.

FIG. 2 is a view similar to FIG. 1 of a shock wave device of the presentinvention propagating a planar wave which emits wave fronts with planewaves as shown in FIG. 1.

FIG. 2 a is a simplified depiction of a pressure pulse/shock wavegenerator having an adjustable exit window along the pressure wave path.The exit window is shown in a focusing position.

FIG. 2 b is a simplified depiction of a pressure pulse/shock wavegenerator having an exit window along the pressure wave path. The exitwindow as shown is positioned at the highest energy divergent position.

FIG. 2 c is a simplified depiction of a pressure pulse/shock wavegenerator having an exit window along the pressure wave path. The exitwindow is shown at a low energy divergent position.

FIG. 3 is a simplified depiction of an electro-hydraulic pressurepulse/shock wave generator having no reflector or focusing element.Thus, the waves of the generator did not pass through a focusing elementprior to exiting it.

FIG. 4 a is a simplified depiction of a pressure pulse/shock wavegenerator having a focusing element in the form of an ellipsoid. Thewaves generated are focused.

FIG. 4 b is a simplified depiction of a pressure pulse/shock wavegenerator having a parabolic reflector element and generating waves thatare disturbed plane.

FIG. 4 c is a simplified depiction of a pressure pulse/shock wavegenerator having a quasi parabolic reflector element (generalizedparaboloid) and generating waves that are nearly plane/have nearly planecharacteristics.

FIG. 4 d is a simplified depiction of a generalized paraboloid withbetter focusing characteristic than a paraboloid in which n=2. Theelectrode usage is shown. The generalized paraboloid, which is aninterpolation (optimization) between two optimized paraboloids for a newelectrode and for a used (burned down) electrode is also shown.

FIG. 5 is a simplified depiction of a pressure pulse/shock wavegenerator being connected to a control/power supply unit.

FIG. 6 is a simplified depiction of a pressure pulse/shock wavegenerator comprising a flat EMSE (electromagnetic shock wave emitter)coil system to generate nearly plane waves as well as an acoustic lens.Convergent wave fronts are leaving the housing via an exit window.

FIG. 7 is a simplified depiction of a pressure pulse/shock wavegenerator having a flat EMSE coil system to generate nearly plane waves.The generator has no reflecting or focusing element. As a result, thepressure pulse/shock waves are leaving the housing via the exit windowunfocused having nearly plane wave characteristics.

FIG. 8 is a simplified depiction of a pressure pulse/shock wavegenerator having a flat piezoceramic plate equipped with a single ornumerous individual piezoceramic elements to generate plane waveswithout a reflecting or focusing element. As a result, the pressurepulse/shock waves are leaving the housing via the exit window unfocusedhaving nearly plane wave characteristics.

FIG. 9 is a simplified depiction of a pressure pulse/shock wavegenerator having a cylindrical EMSE system and a triangular shapedreflecting element to generate plane waves. As a result, the pressurepulse/shock waves are leaving the housing via the exit window unfocusedhaving nearly plane wave characteristics.

FIG. 10 is a simplified depiction of a pressure pulse/shock wave (PP/SW)generator with focusing wave characteristics shown focused with thefocal point or geometrical focal volume being on a substance, the focusbeing targeted on the location X₀.

FIG. 11 is a simplified depiction of a pressure pulse/shock wave (PP/SW)generator with the focusing wave characteristics shown wherein the focusis located a distance X, from the location X₀ of a substance wherein theconverging waves impinge the substance in a convergent off target wavefront.

FIG. 12 is a simplified depiction of a pressure pulse/shock wave (PP/SW)generator with focusing wave characteristics shown wherein the focus islocated a distance X₂ from the mass location X₀ wherein the emitteddivergent waves impinge the substance.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a drawing of a conventional device having a high-voltagegenerator that stores electrical energy in capacitors. Electrode tips 2′and 3′ are electrically connected to the high-voltage unit 7′ and aredisposed in a housing 1 for a reflector 4′. The housing 1 is filled witha liquid W. In a preferred embodiment, the liquid W is water. To keepthe water within the housing, it is sealed by a membrane M. A spark isgenerated between the two electrode tips 2 and 3 which are centered atthe focal point F1 of the ellipsoid, to generate a shock wave 8. Themembrane M provides a contact surface of the device to the treatmentarea. As the shock wave is expanding it will hit the reflector of anellipsoidal shape. The inner surface of reflector 4 has an ellipsoidshape to reflect the shock wave, as at 10 and 10′, toward focal pointF2. The reflected part of the spherical shockwave represented by thespace angle e is determined by the cutoff point (M) of the ellipsoid andby the half axes of a and b of the ellipsoid.

FIG. 2 depicts a device 20′ of the present invention including thehigh-voltage generator 7′ that stores electrical energy in capacitorsand is provided with the electrodes 2′ and 3′. The amount of electricalenergy is given by the voltage and the capacitance and usually thecapacitors are charged to 10 kV to 30 kV, the capacitance being in therange from 10 nF to 50 nF, leading to electrical energy stored in thecapacitors in the range of from 0.5 J to 23 J for an electrohydraulicsystem.

A reflector housing in an embodiment may be made of ceramic, brass,steel, aluminum or other metals. In an embodiment, the housing 9′ iscylindrically shaped. In the housing 9′ is a reflector 15′ which has aparabolic shape (as shown in Fig. In an embodiment, the reflector 15′and housing 9′ may be integrally formed. In an alternate embodiment, thereflector 15′ may be a separate surface from the housing 9′ and a wall 9a of the reflector 15′ has a thickness of approximately 3 mm. Thereflector housing 9′ includes a cavity 9 b that is filled with a fluid Wthat transmits the shockwave. In an embodiment the fluid W is water. Tokeep the water contained within the cavity 9 b, the housing 9′ is sealedby a membrane M. In an embodiment, the membrane M consists of soft PVCand its wall thickness is in the range of approximately 1 to 3 mm. PVChas a good acoustic matching to the water so that the reflection losseswill be low. The membrane M may also provide a contact surface of thedevice to the treatment area. To achieve a good acoustic coupling of theshock wave from the device into the treatment area a coupling gel, suchas ultra sound gel, may be used.

The device 20′ includes a wave directing and shaping structure, such asthe reflector wall that is formed having a parabolic shape. Water iscontained within the paraboloid The paraboloid has an origin O₁ andfocal point In a preferred embodiment, the distance between F1 and O₁ isapproximately 3 mm to 10 mm.

In use, a high-voltage discharge from the capacitor 7′ causes a spark tobe generated between the electrode tips 3′ and 2′, which are disposedsubstantially at the focal point. The spark provides a shock wave sourcethat creates a spherical shock wave illustrated as a circle. The wave isillustrated in FIG. 2 prior to reflection. In an electro hydraulicsystem, the shock wave 8′ generates a plasma bubble. The focal point F1provides a propagation point that is centered between the electrode tipsand 3.

As the plasma bubble expands spherically and cools down, it drives ashock wave in front of it. If the expansion velocity of the plasmabubble is lower than the velocity of sound of the surrounding medium W,a spherical shock wave is released and detaches from the expandingplasma bubble. As the wave propagates, its lower portion will reflectagainst the lower portion of the parabolic reflector and propagate aplanar wave that will move through the reflector cavity The planar wavewill move toward the opening of the cavity which is defined by theintersection with the membrane M of a conical angle r having its apex atthe focal point F1. The wave then propagates through the membrane thatcouples the shock wave and will propagate it through the skin and tissueof the subject which the membrane is placed against.

The energy density of the shock wave is determined for a given energy bythe distance of F1 from the origin point O₁ of the paraboloid. Thereflected part of the spherical shockwave represented by the space angler is determined by the cut-off distance (M) of the paraboloid from itsfocal point. The wave propagates in a way that a flat shock wave 10 and10′ is released from the shock wave device. The wave propagates into thepatient as represented by wave and a wave further in time”. In apreferred embodiment, the paraboloid has an opening 9 c having adiameter which is in the range of approximately 20 mm to 100 mm. In apreferred embodiment, the power density of the wave is in the range of0.01 mJ/mm² to 1 mJ/mm².

In an alternate embodiment, the device 20′ may be piezo electric orelectromagnetic and provide a wave via means other than theelectrohydraulic system depicted in FIG. 2. In such embodiments, a lensmay be used in place of the reflector 15′. In a further alternateembodiment, a rod which forms a cylindrical wave source wave may beused. In such an embodiment, the reflector may have side walls forming aconical angle of approximately 45 degrees in order to develop the planarwave.

The above arrangement depicted in FIG. wherein F1 is approximately 3 mmto 10 mm from the origin of the paraboloid, will provide a wave that hasa proper power density so that the wave can affect tissues in a humanbody in order to cause a therapeutic effect. For example, an energydensity is high enough to trigger a physiological repair response withinthe cell. Such mechanisms may include release of cytokines induction ofheat, shock, protein and other immunological responses. Such responsesmay be generated by a planar shock wave of 50 to 1,000 isonorm bars.This planar wave will penetrate deeply into a human subject so thattissue treatments may be helpful through a large area.

These and other beneficial treatments are made possible by using anapparatus with a shock wave emission either singularly or in an array asdescribed below in the embodiments shown in FIGS. 1-12

FIG. 1 a is a simplified depiction of the a pressure pulse/shock wave(PP/SW) generator, such as a shock wave head, showing focusingcharacteristics of transmitted acoustic pressure pulses. Numeral 1indicates the position of a generalized pressure pulse generator, whichgenerates the pressure pulse and, via a focusing element, focuses itoutside the housing to treat diseases. The diseased organ is generallylocated in or near the focal point which is located in or near position6. At position 17 a water cushion or any other kind of exit window forthe acoustical energy is located.

FIG. 1 b is a simplified depiction of a pressure pulse/shock wavegenerator, such as a shock wave head, with plane wave characteristics.Numeral 1 indicates the position of a pressure pulse generator accordingto the present invention, which generates a pressure pulse which isleaving the housing at the position 17, which may be a water cushion orany other kind of exit window. Somewhat even (also referred to herein as“disturbed”) wave characteristics can be generated, in case a paraboloidis used as a reflecting element, with a point source (e.g. electrode)that is located in the focal point of the paraboloid. The waves will betransmitted into the patient's body via a coupling media such as, e.g.,ultrasound gel or oil and their amplitudes will be attenuated withincreasing distance from the exit window 17.

FIG. 1 c is a simplified depiction of a pressure pulse shock wavegenerator (shock wave head) with divergent wave characteristics. Thedivergent wave fronts may be leaving the exit window 17 at point 11where the amplitude of the wave front is very high. This point 17 couldbe regarded as the source point for the pressure pulses. In FIG. 1 c thepressure pulse source may be a point source, that is, the pressure pulsemay be generated by an electrical discharge of an electrode under waterbetween electrode tips. However, the pressure pulse may also begenerated, for example, by an explosion. The divergent characteristicsof the wave front may be a consequence of the mechanical setup shown inFIG. 2 b.

FIG. 2 a is a simplified depiction of a pressure pulse/shock wavegenerator (shock wave head) according to the present invention having anadjustable or exchangeable (collectively referred to herein as“movable”) housing around the pressure wave path. The apparatus is shownin a focusing position. FIG. 2 a is similar to FIG. 1 a but depicts anouter housing 16 in which the acoustical pathway (pressure wave path) islocated. In a preferred embodiment, this pathway is defined byespecially treated water (for example, temperature controlled,conductivity and gas content adjusted water) and is within a watercushion or within a housing having a permeable membrane, which isacoustically favorable for the transmission of the acoustical pulses. Incertain embodiments, a complete outer housing 16 around the pressurepulse/shock wave generator 1 may be adjusted by moving this housing 16in relation to, e.g., the focusing element in the generator along achannel or pair of channels 75, sliding to a desired location to fix thelocation by tightening a thumb screw 76 by way of example. However, asthe person skilled in the art will appreciate, this is only one of manyembodiments of the present invention. While the figure shows that theexit window 17 may be adjusted by a movement of the complete housing 16relative to the focusing element, it is clear that a similar, if not thesame, effect can be achieved by only moving the exit window, or, in thecase of a water cushion, by filling more water in the volume between thefocusing element and the cushion. FIG. 2 a shows the situation in whichthe arrangement transmits focused pressure pulses.

FIG. 2 b is a simplified depiction of the pressure pulse/shock wavegenerator (shock wave head) having an adjustable or exchangeable housingaround the pressure wave path with the exit window 17 being in thehighest energy divergent position. The configuration shown in FIG. 2 bcan, for example, be generated by moving the housing 16 including theexit window 17, or only the exit window 17 of a water cushion, towardsthe right (as shown in the Figure) to the second focus f2 20 of theacoustic waves. In a preferred embodiment, the energy at the exit windowwill be maximal. Behind the focal point, the waves may be moving withdivergent characteristics 21.

FIG. 2 c is a simplified depiction of the pressure pulse/shock wavegenerator (shock wave head) having an adjustable or exchangeable housingaround the pressure wave path in a low energy divergent position. Theadjustable housing or water cushion is moved or expanded much beyond f2position 20 so that highly divergent wave fronts with low energy densityvalues are leaving the exit window 17 and may be coupled to a patient'sbody. Thus, an appropriate adjustment can change the energy density of awave front without changing its characteristic.

This apparatus may, in certain embodiments, be adjusted/modified/or thecomplete shock wave head or part of it may be exchanged so that thedesired and/or optimal acoustic profile such as one having wave frontswith focused, nearly plane or divergent characteristics can be chosen.

A change of the wave front characteristics may, for example, be achievedby changing the distance of the exit acoustic window relative to thereflector, by changing the reflector geometry, by introducing certainlenses or by removing elements such as lenses that modify the wavesproduced by a pressure pulse/shock wave generating element. Exemplarypressure pulse/shock wave sources that can, for example, be exchangedfor each other to allow an apparatus to generate waves having differentwave front characteristics are described in detail below.

In certain embodiments, the change of the distance of the exit acousticwindow can be accomplished by a sliding movement. However, in otherembodiments of the present invention, in particular, if mechanicalcomplex arrangements, the movement can be an exchange of mechanicalelements.

In one embodiment, mechanical elements that are exchanged to achieve achange in wave front characteristics include the primary pressure pulsegenerating element, the focusing element, the reflecting element, thehousing and the membrane. In another embodiment, the mechanical elementsfurther include a closed fluid volume within the housing in which thepressure pulse is formed and transmitted through the exit window.

In one embodiment, the apparatus of the present invention is used incombination therapy. Here, the characteristics of waves emitted by theapparatus are switched from, for example, focused to divergent or fromdivergent with lower energy density to divergent with higher energydensity. Thus, effects of a pressure pulse treatment can be optimized byusing waves having different characteristics and/or energy densities,respectively.

While the above described universal toolbox of the present inventionprovides versatility, the person skilled in the art will appreciate thatapparatuses that only produce waves having, for example, nearly planecharacteristics, are less mechanically demanding and fulfill therequirements of many users.

As the person skilled in the art will also appreciate that embodimentsshown in drawings 1 a-1 c and 2 a-2 c are independent of the generationprinciple and thus are valid for not only electro-hydraulic shock wavegeneration but also for, but not limited to, PP/SW generation based onelectromagnetic, piezoceramic and ballistic principles. The pressurepulse generators may, in certain embodiments, be equipped with a watercushion that houses water which defines the path of pressure pulse wavesthat is, through which those waves are transmitted. In a preferredembodiment, a patient is coupled via ultrasound gel or oil to theacoustic exit window 17, which can, for example, be an acoustictransparent membrane, a water cushion, a plastic plate or a metal plate.

FIG. 3 is a simplified depiction of the pressure pulse/shock waveapparatus having no focusing reflector or other focusing element. Thegenerated waves emanate from the apparatus without coming into contactwith any focusing elements. FIG. 3 shows, as an example, an electrode asa pressure pulse generating element producing divergent waves 28 behindthe ignition point defined by a spark between the tips of the electrode23, 24.

FIG. 4 a is a simplified depiction of the pressure pulse/shock wavegenerator (shock wave head) having as focusing element an ellipsoid 30.Thus, the generated waves are focused at 6.

FIG. 4 b is a simplified depiction of the pressure pulse/shock wavegenerator (shock wave head) having as a focusing element an paraboloid(y²=2px). Thus, the characteristics of the wave fronts generated behindthe exit window 33, 34, 35, and 36 are disturbed plane (“parallel”), thedisturbance resulting from phenomena ranging from electrode burn down,spark ignition spatial variation to diffraction effects. However, otherphenomena might contribute to the disturbance.

FIG. 4 c is a simplified depiction of the pressure pulse/shock wavegenerator (shock wave head) having as a focusing element a generalizedparaboloid (y^(n)=2px, with 1.2<n<2.8 and n≠2). Thus, thecharacteristics of the wave fronts generated behind the exit window 37,38, 39, and 40 are, compared to the wave fronts generated by aparaboloid (y²=2px), less disturbed, that is, nearly plane (or nearlyparallel or nearly even 37, 38, 39, 40). Thus, conformationaladjustments of a regular paraboloid (y²=2px) to produce a generalizedparaboloid can compensate for disturbances from, e.g., electrode burndown. Thus, in a generalized paraboloid, the characteristics of the wavefront may be nearly plane due to its ability to compensate for phenomenaincluding, but not limited to, burn down of the tips of the electrodeand/or for disturbances caused by diffraction at the aperture of theparaboloid. For example, in a regular paraboloid (y²=2px) with p=1.25,introduction of a new electrode may result in p being about 1.05. If anelectrode is used that adjusts itself to maintain the distance betweenthe electrode tips (“adjustable electrode”) and assuming that theelectrodes burn down is 4 mm (z=4 mm), p will increase to about 1.45. Tocompensate for this burn down, and here the change of p, and to generatenearly plane wave fronts over the life span of an electrode, ageneralized paraboloid having, for example n=1.66 or n=2.5 may be used.An adjustable electrode is, for example, disclosed in U.S. Pat. No.6,217,531.

FIG. 4 d shows sectional views of a number of paraboloids. Numeral 62indicates a paraboloid of the shape y²=2px with p=0.9 as indicated bynumeral 64 at the x axis which specifies the p/2 value (focal point ofthe paraboloid). Two electrode tips of a new electrode 66 (inner tip)and 67 (outer tip) are also shown in the Figure. If the electrodes arefired and the tips are burning down the position of the tips change, forexample, to position 68 and 69 when using an electrode which adjusts itsposition to compensate for the tip burn down. In order to generatepressure pulse/shock waves having nearly plane characteristics, theparaboloid has to be corrected in its p value. The p value for theburned down electrode is indicate by 65 as p/2=1. This value, whichconstitutes a slight exaggeration, was chosen to allow for an easierinterpretation of the Figure. The corresponding paraboloid has the shapeindicated by 61, which is wider than paraboloid 62 because the value ofp is increased. An average paraboloid is indicated by numeral 60 inwhich p=1.25 cm. A generalized paraboloid is indicated by dashed line 63and constitutes a paraboloid having a shape between paraboloids 61 and62. This particular generalized paraboloid was generated by choosing avalue of n≠2 and a p value of about 1.55 cm. The generalized paraboloidcompensates for different p values that result from the electrode burndown and/or adjustment of the electrode tips.

FIG. 5 is a simplified depiction of a set-up of the pressure pulse/shockwave generator 43 (shock wave head) and a control and power supply unit41 for the shock wave head 43 connected via electrical cables 42 whichmay also include water hoses that can be used in the context of thepresent invention. However, as the person skilled in the art willappreciate, other set-ups are possible and within the scope of thepresent invention.

FIG. 6 is a simplified depiction of the pressure pulse/shock wavegenerator (shock wave head) having an electromagnetic flat coil 50 asthe generating element. Because of the plane surface of the acceleratedmetal membrane of this pressure pulse/shock wave generating element, itemits nearly plane waves which are indicated by lines 51. In shock waveheads, an acoustic lens 52 is generally used to focus these waves. Theshape of the lens might vary according to the sound velocity of thematerial it is made of. At the exit window 17 the focused waves emanatefrom the housing and converge towards focal point 6.

FIG. 7 is a simplified depiction of the pressure pulse/shock wavegenerator (shock wave head) having an electromagnetic flat coil 50 asthe generating element. Because of the plane surface of the acceleratedmetal membrane of this generating element, it emits nearly plane waveswhich are indicated by lines 51. No focusing lens or reflecting lens isused to modify the characteristics of the wave fronts of these waves,thus nearly plane waves having nearly plane characteristics are leavingthe housing at exit window 17.

FIG. 8 is a simplified depiction of the pressure pulse/shock wavegenerator (shock wave head) having an piezoceramic flat surface withpiezo crystals 55 as the generating element. Because of the planesurface of this generating element, it emits nearly plane waves whichare indicated by lines 51. No focusing lens or reflecting lens is usedto modify the characteristics of the wave fronts of these waves, thusnearly plane waves are leaving the housing at exit window 17. Emittingsurfaces having other shapes might be used, in particular curvedemitting surfaces such as those shown in FIGS. 4 a to 4 c as well asspherical surfaces. To generate waves having nearly plane or divergentcharacteristics, additional reflecting elements or lenses might be used.The crystals might, alternatively, be stimulated via an electroniccontrol circuit at different times, so that waves having plane ordivergent wave characteristics can be formed even without additionalreflecting elements or lenses.

FIG. 9 is a simplified depiction of the pressure pulse/shock wavegenerator (shock wave head) comprising a cylindrical electromagnet as agenerating element 53 and a first reflector having a triangular shape togenerate nearly plane waves 54 and 51. Other shapes of the reflector oradditional lenses might be used to generate divergent waves as well.

With reference to FIGS. 10, 11 and 12 a schematic view of a shock wavegenerator or source 1 is shown emitting a shock wave front 200 from anexit window 17. The shock wave front 200 has converging waves 202extending to a focal point or focal geometric volume 20 at a locationspaced a distance X from the generator or source 1. Thereafter the wavefront 200 passes from the focal point or geometric volume 20 in adiverging wave pattern as has been discussed in the various other FIGS.1-9 generally.

With particular reference to FIG. 10 a substance 100 is shown generallycentered on the focal point or volume 20 at a location X₀ within thesubstance 100. In this orientation the emitted waves are focused andthus are emitting a high intensity acoustic energy at the location X₀.This location X₀ can be anywhere within or on the substance. Assumingthe substance 100 is a tissue having a mass 102 at location X₀ then thefocus is located directly on the mass 102. In one method of treating atumor or any other type mass 102 these focused waves can be directed todestroy or otherwise reduce the mass 102.

With reference to FIG. 11, the substance 100 is shifted a distance Xtoward the generator or source 1. The substance 100 at location X₀ beingpositioned a distance X−X₁ from the source 1. This insures the substance100 is impinged by converging waves 202 but removed from the focal point20. When the substance 100 is tissue this bombardment of convergingwaves 202 stimulates the cells activating the desired healing responseas previously discussed. This is defined herein as an off targetconverging wave front.

With reference to FIG. 12, the substance 100 is shown shifted or locatedin the diverging wave portion 204 of the wave front 200. As shown X₀ isnow at a distance X₂ from the focal point or geometric volume 20 locatedat a distance X from the source 1. Accordingly X₀ is located a distanceX+X₂ from the source 1. As in FIG. 10 this region of diverging waves 204can be used to stimulate the substance 100 which when the substance is acellular tissue stimulates the cells to produce the desired healingeffect or response.

As shown the use of these acoustic wave forms can be used separately orin combination to achieve the desired therapeutic effect.

Furthermore such acoustic wave forms can be used in combination withdrugs, chemical treatments, irradiation therapy or even physical therapyand when so combined the stimulated cells will more rapidly assist thebody's natural healing response.

The present invention provides an apparatus for an effective treatmentof indications, which benefit from low energy pressure pulse/shock waveshaving nearly plane or even divergent characteristics. For the treatmentof those indications, the procedure to locate the area to which thepressure pulses/shock waves are applied often needs to be less accuratethan, e.g., when kidney stones are destroyed with focused waves. Infact, sometimes the knowledge of the physique of the subject to betreated is sufficient, so that imaging devices like ultrasound, x-ray orsimilar, as they are known from devices used in the destruction ofkidney stones, are not required. For certain indication, it might beadvantageous to a treat an entire area simultaneously, for example ifthe affected tissue is spread out and has a more area like characterrather than a volume like character. One example of such an indicationis spread out muscle pain. The small focal points/focus volumes (definedas −6 dB of the maximum pressure amplitude at a certain energy outputsetting) of a few mm (for example 2-25 mm) produced by focused wavesmight be too small to optimally treat the affected area. The area of thefocal point/focus volume can be enlarged by reducing the focusing oreven by eliminating it all together by using an apparatus according tothe present invention which produces waves having wave fronts withnearly plane or divergent characteristics.

With an unfocused wave having plane, nearly plane wave characteristic,convergent off target or even divergent wave characteristics, the energydensity of the wave may be or may be adjusted to be so low that sideeffects including pain are very minor or even do not exist at all.

In certain embodiments, the apparatus of the present invention is ableto produce waves having energy density values that are below 0.1 mJ/mm²or even as low as 0.000001 mJ/mm². In a preferred embodiment, those lowend values range between 0.1-0.001 mJ/mm². With these low energydensities, side effects are reduced and the dose application is muchmore uniform. Additionally, the possibility of harming surface tissue isreduced when using an apparatus of the present invention that generateswaves having nearly plane or divergent characteristics and largertransmission areas compared to apparatuses using a focused shock wavesource that need to be moved around to cover the affected area. Theapparatus of the present invention also may allow the user to make moreprecise energy density adjustments than an apparatus generating onlyfocused shock waves, which is generally limited in terms of lowering theenergy output.

The treatment of the above mentioned indications are believed to be afirst time use of acoustic shock wave therapy generally with theexception of the heart and pancreas which have been subjected to tissuefocal point targeted by focused shock waves. None of the work done todate has treated the above mentioned indications with convergent,divergent, planar or near-planar acoustic shock waves of low energy.Accordingly the use of acoustic shock waves for treating suchindications as cirrhosis of the liver, cancer, myelodysplasia, stomachulcers, AIDs, Alzheimer's disease, bone cancer, arthritis, emphysema,gout, rheumatic disease, HIV, leprosy, lupus, skin sarcomas, cellulitis,melanomas, osteoporosis, periodontal diseases, pseudoarthrosis, wounds,scars, acne, burns, diabetes, cystic fibrosis, nerve paraplegia orenhancing stem cell reactions are completely new and a breakthrough inmedical treatments of such diseases. As is the use of acoustic shockwaves for germicidal wound cleaning or preventive medical treatments.

It will be appreciated that the apparatuses and processes of the presentinvention can have a variety of embodiments, only a few of which aredisclosed herein. It will be apparent to the artisan that otherembodiments exist and do not depart from the spirit of the invention.Thus, the described embodiments are illustrative and should not beconstrued as restrictive.

1. A method for developing a planar shock wave to be used fortherapeutic purposes for treating living tissue to produce a livingtissue reaction in a subject to which the shock wave is administered,the method comprising the steps of: generating a spark to cause a shockwave; shaping and directing the shock wave to create a planar shockwave; and propagating the planar shock wave toward the subject in theabsence of a focusing lens through an exit window or membrane coupled tothe tissues so that the emitted wave is transmitted unfocused from theexit window or membrane to the treated living tissue with reflectedunfocused flat acoustic waves wherein the planar shock wave generates animmune response in the tissue and has a power density in the range ofapproximately 0.01 mJ/mm² to 1.0 mJ/mm² while avoiding tissue damage. 2.The method of claim 1 further comprising the steps of: providing adevice having a parabolic reflector, an energy source attached to anelectrode tip and wherein the membrane or exit window is disposed acrossa cavity in communication with the parabolic reflector; orienting theelectrode tip generally at a focal point of the parabolic reflector;generating the spark at the electrode tip and developing the shock wave;propagating the shock wave so that it reflects at the parabolicreflector; and propagating the planar shock wave through the membrane orexit window coupled to the subject and directed toward tissue of thesubject to receive the planar wave for therapeutic effect.
 3. The methodof claim 2 wherein the parabolic reflector has an opening having adiameter that is in the range of approximately 20 mm to 100 mm.
 4. Themethod of claim 2 wherein the planar shock wave triggers a physiologicalrepair response in the subject.
 5. A therapeutic method for treatingtissue comprising the steps of: generating a planar shock wave; andcoupling the planar shock wave to the tissue to be treated wherein theplanar shock wave generates an immune response in the tissue and has apower density in the range of approximately 0.01 mJ/mm² to 1.0 mJ/mm²while avoiding tissue damage.
 6. The method of claim 5 furthercomprising the steps of: providing a treatment device that develops theplanar shock wave; orienting the treatment device adjacent to a tissuearea; and activating the tissue in order to cause a chemical releasefrom the tissue cells.
 7. The method of claim 5 wherein the shock waveis generated by electro hydraulic, electromagnetic or piezoelectricmeans.
 8. The method of claim 5 wherein the generating includes:generating a spark to develop a shock wave, and reflecting the shockwave from a parabolic reflector to form a planar shock wave.
 9. Themethod of claim 5 wherein the planar shock wave is administered at apower density sufficient to cause the tissue to be activated to releasea protein for generating an immune response.